Intravascular catheters such as angiographic or angioplasty catheters are introduced from the exterior of a patient into an artery or vein. After such an introduction, the catheter is advanced and maneuvered through the arteriovenous system to a desired site, which may be an area of arterial stenosis, or an area from which the x-ray contrast media is injected into the system. As described for example in Stevens U.S. Pat. No. 4,000,739, such a catheter may be emplaced by first inserting a hollow needle with a trocar through the skin into the lumen of the desired blood vessel. Following this, a guidewire is passed through the needle and advanced up the artery or vein toward the desired area. The needle can then be removed, leaving the guidewire in the vessel.
Following this, a catheter introducer comprising a tubular sheath and a removable, hollow stylet or dilator unit may be advanced together over the wire into the vessel. Then, the guidewire and the dilator unit may be removed, leaving only the sheath of the catheter introducer member present in the vessel. Then, desired catheters can be advanced through the sheath into the vessel, particularly an artery, while reliably maintaining a seal against blood loss as the catheter is advanced, and also between the times that a catheter is being advanced or maintained in the blood vessel.
The sheath of the catheter introducer carries a hub, which has partition-type hemostasis valve means on its proximal end, to avoid uncontrolled bleeding and air embolism. The dilator unit, and then respective catheters as desired, pass through this hemostasis valve. Specifically, hemostasis valves of the design disclosed in Hillstead U.S. Pat. Nos. 4,798,594 and 4,895,565, and Weinstein, U.S. Pat. No. 4,626,245, are known among numerous other designs. In the above designs, the elastomeric partition is carried by the hub, and defines a special slit which is particularly adapted to provide good sealing about an advancing catheter which passes through the catheter introducer. Improvements in the frictional resistance to catheter advancement are provided over a conventional, straight slit by the above.
In Goode and Weinstein copending application Ser. No. 08/077,242 cited above, a partition valve for a catheter hub on a catheter sheath introducer or the like is provided, in which the central portion of the partition which carries the slit is of reduced thickness compared with peripheral portions, which peripheral portions are used for securance of the partition within the hub. By this means and other improvements described therein, improvements in both sealing of a catheter extending through the hemostasis valve, and reduction of friction encountered by the catheter, are provided.
By this invention, yet further improvements are provided in a partition type hemostasis valve, having improved sealing capability coupled with reduced friction for a catheter or other elongated member which is passing through the partition valve. Thus, the valve of this invention provides improved utility and clinical benefits to catheter sheath introducers and the like. Additionally, tearing of the partition at the slit ends during catheter advancement or retraction can be further reduced in the partition valves of this invention, even without reinforcement of the slit ends.